How to undervolt your laptop for longer, cooler performance
By Evan Blass 
posted January 24th 2006 8:00AM
posted January 24th 2006 8:00AM
Most of the PC hacks that you come across are
usually in the realm of overclocking or case modding, so it's nice to find an easily-implemented, software-based
performance tweak once in awhile that delivers some real results. Well NordicHardware has an article that describes
just such a procedure, where Fredrik Andersson steps you through the process of undervolting your laptop. Although as
Andresson points out, the terminology is not an accurate reflection of the adjustment being performed, undervolting
refers to stepping down the voltage that your CPU requires by several fractions of a volt. The end result of the tweaks
that NH guides you through is up to ten minutes more running time and several degrees less heat dispersion, all without
affecting the notebook's performance. As with all of the helpful hints that we pass along, this modification is done at
your own risk (i.e. don't come crying to us if you break your lappie).[Via Slashdot]
My 1.86GHZ came running at .988 volts at Battery time of 4:10. I used centrino hardware control and dropped it to just .892v and battery time went to 4:50. From what I have been seeing I can probably go lower. Now combines with undervolting and turning my brightness all the way down , battery time is 5:10.
Gateway MX8525 , PM 1.86GHZ ,1GB DDR,100GB HDD, 17" Screen, 64MB ATI X700
how can i find out what is the lowest the voltage i can set my cpu to without having any trouble with not having enough power? thank you in advance
Affecting, not effecting.
Only 10 extra minutes? Might not be worth it, I thought maybe he'd manage to squeeze an extra half-hour or more.
Up to 10 minutes more? Hardly seems worth it for the risk involved.
there really is no risk with this, other than maybe crashing your laptop for going to0 low of a voltage. Another reason this is handy is if you are like me and your laptop wont lower its clock speed to save battery. I can lower my 1.86 ghz dothan core to around 900mhz and get good performance on web browsing and save a ton on battery it appears
Turn down the backlight, you'll get way more than 10 more minutes of time out of the battery. What a waste of programming time/blogging time.
under voltage means potential current spikes whenever a device needs a high voltage suddenly and finds there isn't enough power available. God knows what kind of damage doing this long term does to your laptop
Undervolt??? Blah!
Up to 10 minutes means from 00:01 seconds to 9:59 minutes.
But sure!
I always thought this sort of thing should be easier to do... Even if it was just intels speed step being user customisable.
Peter
This is a decent guide for Turion users, but people with a Pentium M should use Centrino Hardware Control (Google it.) It has built-in undervolting support.
People: the point of undervolting is to cool the laptop and extend the life of the CPU. You don't lose any performance, for reasons the guide explains early on. Undervolting works wonders for those purposes. While my laptop (Inspiron 6000) is a desktop replacement rather than an ultra-portable, I would guess that decent undervolting of an ultra-portable would have more benefits in terms of battery life than the laptop used in this guide, more along the lines of 30 minutes instead of 10.
I hope undervolting catches on in laptop reviews: it'll be interesting to see what undervolting a MacBook Pro, or the iBook's replacement, would do for battery life.
I don't have a laptop, but if I could get a free 10 mins for the price of well...nothing, I'd take it in a heartbeat.
All these little tweaks add up.
I've done this with my last 3 laptops and can say that it saves more than 10 minutes. I've used both RMClock and CHC (Centrino Hardware controller). One of the laptops had the Fan going off ALL the time, which was solved with undervolting. Another one ran pretty warm which was also solved by this. The battery lasting longer is just an added bonus to what this program really does.
I only can support Notebook Hardware Control (aka Centrino Hardware Control). Undervolting is easy with that app and a table with "secure" voltages is supplied. The effect was about an hour extra time using all the power optimizing features offered.
I undervolt my CPU. I get anywhere between 10 and 30 more minutes of battery. Where I save the most is not the actual power savings from the the CPU, but because the CPU is running cooler, the fans don't come on as much. In fact, when I am on battery, they barely come on at all.
I have a Dell i9300 (2.0GHz, 2GB of RAM, 6800Go, WUXGA screen) and I get about 3 hours out of my battery. That's pretty good if you ask me.
With all the concern and marketing hoopla about battery time on laptops, why don't they do this straight from the factory if it doesn't affect performance?
#12, because there's a small chance that you might have a "dud" of a chip which might require the full suggested voltage to operate normally. Think about how they "suggest" that an elevator maximum weight is 2500lbs, when it could probably safely handle 3000lbs. They want a "safety" buffer.
Yep, the key reason to do this is fan noise. My laptop sounded like a friggin blender before I undervolted it. Now it's almost always silent.
After spending half an hour trying to do this to my laptop... I found out that it only works on Pentium M processors and NOT on Pentium Mobile 4 like the one I have. Unless i'm mistaken, this won't work for me.
I have a Compaq 2568cl